Ruby SAML Identity Provider (IdP)

Forked from https://github.com/lawrencepit/ruby-saml-idp

The ruby SAML Identity Provider library is for implementing the server side of SAML authentication. It allows your application to act as an IdP (Identity Provider) using the SAML v2.0 protocol. It provides a means for managing authentication requests and confirmation responses for SPs (Service Providers).

This was originally setup by @lawrencepit to test SAML Clients. I took it closer to a real SAML IDP implementation.

Installation and Usage

Add this to your Gemfile:

    gem 'saml_idp'

Not using rails?

Include SamlIdp::Controller and see the examples that use rails. It should be straightforward for you.

Basically, you call decode_request(params[:SAMLRequest]) on an incoming request and then use the value saml_acs_url to determine the source for which you need to authenticate a user. If the signature (Signature) and signing algorithm (SigAlg) are provided as external parameters in the request, you can pass those parameters as decode_request(params[:SAMLRequest], params[:Signature], params[:SigAlg], params[:RelayState]). Then, you can verify the request signature with the valid? method.

How you authenticate a user is entirely up to you.

Once a user has successfully authenticated on your system send the Service Provider a SAMLResponse by posting to saml_acs_url the parameter SAMLResponse with the return value from a call to encode_response(user_email).

Using rails?

Check out our Wiki page for Rails integration Rails Integration guide

Configuration

Signed assertions and Signed Response

By default SAML Assertion will be signed with an algorithm which defined to config.algorithm, because SAML assertions contain secure information used for authentication such as NameID. Besides that, signing assertions could be optional and can be defined with config.signed_assertion option. Setting this configuration flag to false will add raw assertions on the response instead of signed ones. If the response is encrypted the config.signed_assertion will be ignored and all assertions will be signed.

Signing SAML Response is optional, but some security perspective SP services might require Response message itself must be signed. For that, you can enable it with signed_message: true option for encode_response(user_email, signed_message: true) method. More about SAML spec

Signing algorithm

Following algorithms you can set in your response signing algorithm :sha1 - RSA-SHA1 default value but not recommended to production environment Highly recommended to use one of following algorithm, suit with your computing power. :sha256 - RSA-SHA256 :sha384 - RSA-SHA384 :sha512 - RSA-SHA512

Be sure to load a file like this during your app initialization:

SamlIdp.configure do |config|
  base = "http://example.com"

  config.x509_certificate = <<-CERT
-----BEGIN CERTIFICATE-----
CERTIFICATE DATA
-----END CERTIFICATE-----
CERT

  config.secret_key = <<-CERT
-----BEGIN RSA PRIVATE KEY-----
KEY DATA
-----END RSA PRIVATE KEY-----
CERT

  # x509_certificate, secret_key, and password may also be set from within a proc, for example:
  # config.x509_certificate = -> { File.read("cert.pem") }
  # config.secret_key = -> { SecretKeyFinder.key_for(id: 1) }
  # config.password = -> { "password" }

  # config.password = "secret_key_password"
  # config.algorithm = :sha256                                    # Default: sha1 only for development.
  # config.organization_name = "Your Organization"
  # config.organization_url = "http://example.com"
  # config.base_saml_location = "#{base}/saml"
  # config.reference_id_generator                                 # Default: -> { SecureRandom.uuid }
  # config.single_logout_service_post_location = "#{base}/saml/logout"
  # config.single_logout_service_redirect_location = "#{base}/saml/logout"
  # config.attribute_service_location = "#{base}/saml/attributes"
  # config.single_service_post_location = "#{base}/saml/auth"
  # config.session_expiry = 86400                                 # Default: 0 which means never
  # config.signed_assertion = false                               # Default: true which means signed assertions on the SAML Response
  # config.compress = true                                        # Default: false which means the SAML Response is not being compressed
  # config.logger = ::Logger.new($stdout)                         # Default: if in Rails context - Rails.logger, else ->(msg) { puts msg }. Works with either a Ruby Logger or a lambda

  # Principal (e.g. User) is passed in when you `encode_response`
  #
  # config.name_id.formats =
  #   {                         # All 2.0
  #     email_address: -> (principal) { principal.email_address },
  #     transient: -> (principal) { principal.id },
  #     persistent: -> (p) { p.id },
  #   }
  #   OR
  #
  #   {
  #     "1.1" => {
  #       email_address: -> (principal) { principal.email_address },
  #     },
  #     "2.0" => {
  #       transient: -> (principal) { principal.email_address },
  #       persistent: -> (p) { p.id },
  #     },
  #   }

  # If Principal responds to a method called `asserted_attributes`
  # the return value of that method will be used in lieu of the
  # attributes defined here in the global space. This allows for
  # per-user attribute definitions.
  #
  ## EXAMPLE **
  # class User
  #   def asserted_attributes
  #     {
  #       phone: { getter: :phone },
  #       email: {
  #         getter: :email,
  #         name_format: Saml::XML::Namespaces::Formats::NameId::EMAIL_ADDRESS,
  #         name_id_format: Saml::XML::Namespaces::Formats::NameId::EMAIL_ADDRESS
  #       }
  #     }
  #   end
  # end
  #
  # If you have a method called `asserted_attributes` in your Principal class,
  # there is no need to define it here in the config.

  # config.attributes # =>
  #   {
  #     <friendly_name> => {                                                  # required (ex "eduPersonAffiliation")
  #       "name" => <attrname>                                                # required (ex "urn:oid:1.3.6.1.4.1.5923.1.1.1.1")
  #       "name_format" => "urn:oasis:names:tc:SAML:2.0:attrname-format:uri", # not required
  #       "getter" => ->(principal) {                                         # not required
  #         principal.get_eduPersonAffiliation                                # If no "getter" defined, will try
  #       }                                                                   # `principal.eduPersonAffiliation`, or no values will
  #    }                                                                      # be output
  #
  ## EXAMPLE ##
  # config.attributes = {
  #   GivenName: {
  #     getter: :first_name,
  #   },
  #   SurName: {
  #     getter: :last_name,
  #   },
  # }
  ## EXAMPLE ##

  # config.technical_contact.company = "Example"
  # config.technical_contact.given_name = "Jonny"
  # config.technical_contact.sur_name = "Support"
  # config.technical_contact.telephone = "55555555555"
  # config.technical_contact.email_address = "example@example.com"

  service_providers = {
    "some-issuer-url.com/saml" => {
      fingerprint: "9E:65:2E:03:06:8D:80:F2:86:C7:6C:77:A1:D9:14:97:0A:4D:F4:4D",
      metadata_url: "http://some-issuer-url.com/saml/metadata",

      # We now validate AssertionConsumerServiceURL will match the MetadataURL set above.
      # *If* it's not going to match your Metadata URL's Host, then set this so we can validate the host using this list
      response_hosts: ["foo.some-issuer-url.com"]
    },
  }

  # `identifier` is the entity_id or issuer of the Service Provider,
  # settings is an IncomingMetadata object which has a to_h method that needs to be persisted
  config.service_provider.metadata_persister = ->(identifier, settings) {
    fname = identifier.to_s.gsub(/\/|:/,"_")
    FileUtils.mkdir_p(Rails.root.join('cache', 'saml', 'metadata').to_s)
    File.open Rails.root.join("cache/saml/metadata/#{fname}"), "r+b" do |f|
      Marshal.dump settings.to_h, f
    end
  }

  # `identifier` is the entity_id or issuer of the Service Provider,
  # `service_provider` is a ServiceProvider object. Based on the `identifier` or the
  # `service_provider` you should return the settings.to_h from above
  config.service_provider.persisted_metadata_getter = ->(identifier, service_provider){
    fname = identifier.to_s.gsub(/\/|:/,"_")
    FileUtils.mkdir_p(Rails.root.join('cache', 'saml', 'metadata').to_s)
    full_filename = Rails.root.join("cache/saml/metadata/#{fname}")
    if File.file?(full_filename)
      File.open full_filename, "rb" do |f|
        Marshal.load f
      end
    end
  }

  # Find ServiceProvider metadata_url and fingerprint based on our settings
  config.service_provider.finder = ->(issuer_or_entity_id) do
    service_providers[issuer_or_entity_id]
  end
end

Keys and Secrets

To generate the SAML Response it uses a default X.509 certificate and secret key... which isn't so secret. You can find them in SamlIdp::Default. The X.509 certificate is valid until year 2032. Obviously you shouldn't use these if you intend to use this in production environments. In that case, within the controller set the properties x509_certificate and secret_key using a prepend_before_action callback within the current request context or set them globally via the SamlIdp.config.x509_certificate and SamlIdp.config.secret_key properties.

The fingerprint to use, if you use the default X.509 certificate of this gem, is:

  9E:65:2E:03:06:8D:80:F2:86:C7:6C:77:A1:D9:14:97:0A:4D:F4:4D

Fingerprint

The gem provides an helper to generate a fingerprint for a X.509 certificate. The second parameter is optional and default to your configuration SamlIdp.config.algorithm

  SamlIdp::Fingerprint.certificate_digest(x509_cert, :sha512)

Service Providers

To act as a Service Provider which generates SAML Requests and can react to SAML Responses use the excellent ruby-saml gem.

Author

Jon Phenow, jon@jphenow.com, jphenow.com, @jphenow

Lawrence Pit, lawrence.pit@gmail.com, lawrencepit.com, @lawrencepit

Copyright

See LICENSE for details.

saml_idp

Development

Runtime